The disclosure relates generally to acoustic attenuation, and more particularly, to a silencer duct having a silencing duct body and a silencing element extending therethrough and couplers extending axially from the duct body.
Noise reduction systems are used on a large variety of industrial machines such as turbomachines to reduce the acoustic impact to surrounding areas. In gas turbine systems, for example, noise reduction systems may be employed in the turbomachine inlet duct, gas turbine enclosures and barrier walls. Traditionally, to attain the necessary acoustic reduction requirements, silencer panels and acoustically treated walls are used in the noisy areas. One mechanism to reduce acoustic impact is to treat walls with acoustic absorbing material. Another mechanism is to place silencer panels in areas where noise reduction is required, such as a working fluid flow path in an intake system duct.
With regard to ducts, each duct typically includes a frame having a number of silencer panels therein. Each panel typically includes an acoustic absorbing material such as mineral/glass wool positioned by a metal supporting member and surrounded by an enclosure including stainless steel perforated sheets on the sides thereof. The sheets are held together by stainless steel end caps. The stainless steel perforated sheets are typically welded to the supporting members that hold the acoustic absorbing material. The perforated stainless steel sheets hold the acoustic absorbing material intact with the supporting members and propagate the sound waves through the perforations into the acoustic absorbing material. The ducts are also typically made of carbon or a metal, such as steel or stainless steel. Use of steel for the ducts and silencer panel enclosures presents a number of challenges. For example, the enclosures are very heavy, and are also difficult and costly to manufacture due to the cost of the material and the need for welding to form the ducts and panels. In addition, the panels must be welded in place to the surrounding metal duct and must be custom fit for a particular sized duct, but frequently cannot be formed in custom shapes due to the cost and difficulty to manufacture. The frames created with the silencer panels are also typically very large in relative size, and in particular, length.